diff --git a/source/MaterialXGenShader/OcioColorManagementSystem.cpp b/source/MaterialXGenShader/OcioColorManagementSystem.cpp
index e280a18555..5b59d9f172 100644
--- a/source/MaterialXGenShader/OcioColorManagementSystem.cpp
+++ b/source/MaterialXGenShader/OcioColorManagementSystem.cpp
@@ -154,8 +154,35 @@ NodeDefPtr OcioColorManagementSystemImpl::getNodeDef(const ColorSpaceTransform&
         return {};
     }
 
+    // Build a function name from the source/target color space names and the first
+    // six characters of the cache ID.  Each name component is sanitized individually:
+    // invalid characters are replaced with underscores and consecutive underscores are
+    // collapsed to one so that OCIO's own identifier normalizer cannot produce a
+    // different name than the one we register on the node def.
+    auto sanitizeName = [](const string& s) -> string
+    {
+        string result = createValidName(s);
+        string collapsed;
+        bool prevUnderscore = false;
+        for (char c : result)
+        {
+            if (c == '_')
+            {
+                if (!prevUnderscore)
+                    collapsed += c;
+                prevUnderscore = true;
+            }
+            else
+            {
+                collapsed += c;
+                prevUnderscore = false;
+            }
+        }
+        return collapsed;
+    };
     static const auto NODE_NAME = string{ "ocio_color_conversion" };
-    const auto functionName = NODE_NAME + "_" + processor->getCacheID();
+    const string cacheID = processor->getCacheID();
+    const auto functionName = NODE_NAME + "_" + sanitizeName(sourceColorSpace) + "_to_" + sanitizeName(targetColorSpace) + "_" + cacheID.substr(0, 6);
     const auto implName = OcioColorManagementSystem::IMPL_PREFIX + functionName + "_" + transform.type.getName();
     const auto nodeDefName = ND_PREFIX + functionName + "_" + transform.type.getName();
     auto nodeDef = document->getNodeDef(nodeDefName);
diff --git a/source/MaterialXGenShader/ShaderGraph.cpp b/source/MaterialXGenShader/ShaderGraph.cpp
index b0f07c7d92..4e3510450f 100644
--- a/source/MaterialXGenShader/ShaderGraph.cpp
+++ b/source/MaterialXGenShader/ShaderGraph.cpp
@@ -12,7 +12,6 @@
 
 #include <MaterialXTrace/Tracing.h>
 
-#include <iostream>
 #include <queue>
 
 MATERIALX_NAMESPACE_BEGIN
@@ -1227,8 +1226,8 @@ void ShaderGraph::populateColorTransformMap(ColorManagementSystemPtr colorManage
             }
             else
             {
-                std::cerr << "Unsupported color space transform from " <<
-                              sourceColorSpace << " to " << targetColorSpace << std::endl;
+                throw ExceptionShaderGenError("Unsupported color space transform from '" +
+                                              sourceColorSpace + "' to '" + targetColorSpace + "'.");
             }
         }
     }
diff --git a/source/MaterialXTest/MaterialXGenMdl/GenMdl.h b/source/MaterialXTest/MaterialXGenMdl/GenMdl.h
index 64b47caab9..0e16c37020 100644
--- a/source/MaterialXTest/MaterialXGenMdl/GenMdl.h
+++ b/source/MaterialXTest/MaterialXGenMdl/GenMdl.h
@@ -76,7 +76,8 @@ class MdlShaderGeneratorTester : public GenShaderUtil::ShaderGeneratorTester
     // Ignore certain .mtlx files
     void addSkipFiles() override
     {
-        // no additional files are skipped
+        // ocio_color_management.mtlx uses color spaces which require OCIO and is not supported by MDL.
+        _skipFiles.insert("ocio_color_management.mtlx");
         ShaderGeneratorTester::addSkipFiles();
     }
 
diff --git a/source/MaterialXTest/MaterialXGenMsl/GenMsl.h b/source/MaterialXTest/MaterialXGenMsl/GenMsl.h
index 2371cfa5e9..af8cdf2d58 100644
--- a/source/MaterialXTest/MaterialXGenMsl/GenMsl.h
+++ b/source/MaterialXTest/MaterialXGenMsl/GenMsl.h
@@ -45,6 +45,7 @@ class MslShaderGeneratorTester : public GenShaderUtil::ShaderGeneratorTester
     {
         // To skip specific files for this render target, add them as below:
         // _skipFiles.insert("example.mtlx");
+        ParentClass::addSkipFiles();
     }
 
     void setupDependentLibraries() override
diff --git a/source/MaterialXTest/MaterialXGenShader/GenShaderUtil.cpp b/source/MaterialXTest/MaterialXGenShader/GenShaderUtil.cpp
index 166a18f691..79fff3da4e 100644
--- a/source/MaterialXTest/MaterialXGenShader/GenShaderUtil.cpp
+++ b/source/MaterialXTest/MaterialXGenShader/GenShaderUtil.cpp
@@ -741,6 +741,12 @@ void ShaderGeneratorTester::validate(const mx::GenOptions& generateOptions, cons
         context.getOptions().targetDistanceUnit = _defaultDistanceUnit;
     }
 
+    // Define target color space if required
+    if (context.getOptions().targetColorSpaceOverride.empty())
+    {
+        context.getOptions().targetColorSpaceOverride = "lin_rec709";
+    }
+
     // Check if a binding context has been set.
     bool bindingContextUsed = _userData.count(mx::HW::USER_DATA_BINDING_CONTEXT) > 0;
 
diff --git a/source/MaterialXTest/MaterialXGenShader/GenShaderUtil.h b/source/MaterialXTest/MaterialXGenShader/GenShaderUtil.h
index de58775eae..4ca7d7f34e 100644
--- a/source/MaterialXTest/MaterialXGenShader/GenShaderUtil.h
+++ b/source/MaterialXTest/MaterialXGenShader/GenShaderUtil.h
@@ -199,7 +199,13 @@ class ShaderGeneratorTester
     virtual void setTestStages() = 0;
 
     // Add files in to not examine
-    virtual void addSkipFiles() { };
+    virtual void addSkipFiles()
+    {
+#ifndef MATERIALX_BUILD_OCIO
+        // ocio_color_management.mtlx uses color spaces which require OCIO.
+        _skipFiles.insert("ocio_color_management.mtlx");
+#endif
+    };
 
     // Add nodedefs to not examine
     virtual void addSkipNodeDefs() { };
diff --git a/source/MaterialXTest/MaterialXGenSlang/GenSlang.h b/source/MaterialXTest/MaterialXGenSlang/GenSlang.h
index 453b891533..e47d29fa29 100644
--- a/source/MaterialXTest/MaterialXGenSlang/GenSlang.h
+++ b/source/MaterialXTest/MaterialXGenSlang/GenSlang.h
@@ -30,6 +30,13 @@ class SlangShaderGeneratorTester : public GenShaderUtil::ShaderGeneratorTester
     }
 
     // Ignore trying to create shader code for displacementshaders
+    void addSkipFiles() override
+    {
+        // ocio_color_management.mtlx uses color spaces which require OCIO and is not supported by Slang.
+        _skipFiles.insert("ocio_color_management.mtlx");
+        ParentClass::addSkipFiles();
+    }
+
     void addSkipNodeDefs() override
     {
         _skipNodeDefs.insert("ND_displacement_float");
diff --git a/source/MaterialXTest/MaterialXRender/RenderUtil.h b/source/MaterialXTest/MaterialXRender/RenderUtil.h
index 7002e3b1ae..7bedd49dcb 100644
--- a/source/MaterialXTest/MaterialXRender/RenderUtil.h
+++ b/source/MaterialXTest/MaterialXRender/RenderUtil.h
@@ -274,7 +274,13 @@ class ShaderRenderTester
     void addAdditionalTestStreams(mx::MeshPtr mesh);
 
     // Add any paths to explicitly skip here
-    virtual void addSkipFiles() {}
+    virtual void addSkipFiles()
+    {
+#ifndef MATERIALX_BUILD_OCIO
+        // ocio_color_management.mtlx uses color spaces which require OCIO.
+        _skipFiles.insert("ocio_color_management.mtlx");
+#endif
+    }
 
     // Read test suite options and check if this target should run.
     bool loadOptions(const mx::FilePath& optionsFilePath, TestRunState& runState);